1. Field of Invention.
This invention is in the field of laminated glass and in particular it relates to coated glass sheets where it is desirable to improve structural characteristics through the addition of adhesive or adhesives and a flexible, thin plastic film or films. Flexible thin film systems can be specially surface pretreated to achieve substantially enhanced or improved performance characteristics when laminated to monolithic glass. Specific applications include the shatterproofing of glass, the addition of unique solar control performance characteristics to glass, the addition of electrical static dissipation characteristics to glass, the creation of an antifogging monolithic glass material, etc.
2. Prior Art.
In the past, lamination of glass has been accomplished by mating two sheets of glass using either some form of catalyzed bonding agent, or by placing a piece of polyvinyl butyral (PVB) between two pieces of glass and subjecting the construction to a combination of heat and pressure which liquifies the PVB material, thereby bonding the two sheets of glass into a single laminated structure. These forms of laminations have been utilized principally with glass for the primary purpose of creating a safety glazing material. While solar control or other properties can be incorporated into these glass structures by using sheet goods which have been specially surface coated, such combinations are expensive and limited in their variations by virtue of the expense and difficulty associated with treating and metallizing rigid sheet glass.
Retrofit film systems have been introduced for application to existing windows, and these films are applied to a wide variety of glass which is already in-place. These film systems utilize a pressure sensitive adhesive which has been factory applied to the film. Such film constructions have traditionally been used for the purpose of solar control and the shatterproofing of the glazed glass.
Also known is the so-called antilacerative windshield. This laminated glass system consists of two pieces of glass combined through the use of polyvinyl butryal, with the inner side of the glass treated with a secondary antilacertative flexible film. The flexible polyester film consisted of a PET film laminated to a second flexible sheet of PVB which in turn was formed to the glass and then placed under heat and pressure causing the secondary or antilacerative film to both bond and conform to the contours of the windshield.
Traditional laminated glass forming techniques seek principally to use thinner sheets of glass to make a thicker, safer monolithic material which sometimes possesses additional unique properties such as solar load reduction, heat retention, sound reduction, etc. Additionally, usage of thinner glass to create thicker structures often results in a more brittle glass combination ultimately causing high incidents of glass failure. Solar control films, as described above, can be applied in a factory setting by using a pretreated PSA adhesive coated flexible film. The visual quality of the lamination is limited by the quality of the pressure sensitive application made by the film supplier. Additionally, small particulate on the glass cannot be absorbed by a thin, fully cured pressure sensitive film system, thereby forming so-called tents or bubbles. Antilacerative structures as described above are currently used to provide additional safety and may offer in the future enhanced performance characteristics for glass.